Re: [boost] intrusive_ptr explicit constructor

From: colin.rafferty_at_[hidden]
Date: 2004-10-22 09:11:12

colin rafferty wrote:
> Peter Dimov wrote:
>> Colin Rafferty wrote:

>>> Shouldn't the constructor in intrusive_ptr be explicit?

>> No, the constructor is implicit by design. Do you have a case where the 
>> implicit constructor causes problems? 

> Sure, this is the same problem as for shared_ptr<>.

>     extern void foo(const intrusive_ptr<Bar>&);

>     void baz()
>     {
>         Bar* bar = new Bar;
>         foo(bar);               // oops!
>         delete bar;
>     }

> I thought I was passing a raw pointer into foo(), but I'm actually
> creating a temporary intrusive_ptr<Bar>, passing that in, and then
> destroying the temporary and the pointer.

More generally, the problem is that intrusive_ptr<> destroys the
object it is passed (on destruction), and having a conversion
constructor makes it very easy for a programmer to make a mistake
(like above).

Can someone please fix this to make the conversion constructor
explicit?

Thanks.

-- 
Colin